This invention relates generally to a method of making ball bearing retainers and more particularly to a method of making one-piece ball bearing retainers.
Many types of prior art ball bearing retainers and cages have been used. One of the major types includes welded metal retainers where two halves are welded together. These welded two-piece retainers have fair wrap-around and conformity to the ball shape. Operating temperature is limited by the lubricant and not by the retainer. However, it is difficult to ensure 100 percent good welds with a welded two-piece retainer design.
Riveted two-piece metal retainers are similar to welded two-piece metal retainers except the two halves are riveted together rather than welded. This type retainer requires many small rivets that are difficult to insert. Visual inspection is more accurate than with welded retainers; however, poor riveting may occur. Similar, mechanically interlocked retainers also require two halves and may be difficult to fasten together.
Spring finger-type retainers offer a one-piece design but are difficult to make with sufficient ball contacting surface or wrap-around. Spring finger-type retainers usually require special heat treating. Polymer retainers offer one-piece design and have good wrap-around and ball conformity. However, polymer retainers are limited to lower temperature applications.
One proposed metal retainer is formed as one-piece and is formed by fashioning a sheet metal ring into an undulatory form with open loops or ball pockets spaced apart by U-shaped connecting portions. After the balls are placed into the pockets, the U-shaped connecting portions are upset causing the sides of the U-shaped connecting portions to spread and partially conform to the contour of the balls. However, a retainer of this proposed design would not have good resistance to ball collision forces during bearing operation and would not be rigid.
The foregoing illustrates limitations known to exist in present ball bearing retainers. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.